some optimizations, more constness, mor compiler flags

CustomModels/channelmodel.cpp

CustomModels/emojismodel.cpp

ddpRequests/ddploginrequest.cpp

ddpRequests/rocketchatsubscribeusernotify.cpp

repos/abstractbaserepository.cpp

repos/abstractbaserepository.h

repos/channelrepository.cpp

repos/channelrepository.h

repos/emojirepo.cpp

repos/emojirepo.h

repos/entities/emoji.cpp

repos/entities/emoji.h

repos/entities/loginmethod.cpp

repos/entities/loginmethod.h

repos/entities/rocketchatattachment.cpp

repos/entities/rocketchatattachment.h

repos/entities/rocketchatchannel.cpp

repos/entities/rocketchatchannel.h

repos/entities/rocketchatmessage.cpp

repos/entities/rocketchatmessage.h